Nelson Mandela is "in good spirits" and making steady progress after a second day in hospital, in the latest health scare for the revered peace icon.

Mr Mandela was admitted to hospital with a recurrence of a lung infection late on Wednesday night (local time).

"He was in good spirits, he had a full breakfast, and the doctors report that he's making steady progress," South Africa's presidency spokesman Mac Maharaj said.

"He sat up and had his breakfast in bed."

The update from his doctors was positive but officials also said it should be also seen with caution.

He was in good spirits, he had a full breakfast, and the doctors report that he's making steady progress, He sat up and had his breakfast in bed.

South Africa presidency spokesman Mac Maharaj

"Yes, indeed it is good news but we need to be cautious, bear in mind his age," added Mr Maharaj, who served time with Mr Mandela on Robben island.

Yesterday, president Jacob Zuma sought to reassure South Africans the country's anti-apartheid hero and first black president was in good hands.

"The country must not panic, Madiba is fine," he said, referring to Mr Mandela by his clan name.

It is the second time this month that the Nobel Peace Prize winner has been admitted to hospital, after spending a night for checkups on March 9.

That followed a nearly three-week hospital stay in December 2012, when he was treated for another lung infection and underwent gallstone surgery, after which he was released for home-based care.

Mr Mandela was diagnosed with early-stage tuberculosis in 1988 during his near three-decades in prison under the white-minority apartheid regime and has long had problems with his lungs. He has also had treatment for prostate cancer and suffered stomach ailments.

Tata (father) is doing well. He's responding very well to treatment.

Nelson Mandela's ex-wife Winnie Madikizela-Mandela

His ex-wife Winnie Madikizela-Mandela told the public broadcaster SABC that "Tata (father) is doing well".

"He's responding very well to treatment," said Ms Madikizela-Mandela, who attended a church service in Soweto where Mr Mandela was prayed for.

The latest series of hospitalisations has triggered an outpouring of prayers for the former president, but has also seen South Africans come to terms with the mortality of their national hero.

"In Zulu, when someone passes away who is very old, people say he or she has gone home. I think those are some of the things we should be thinking about," Mr Zuma said Thursday.

The name and location of the hospital where Mr Mandela is being treated were not disclosed, to allow the medical team to focus on their work and to shield the family from the intense media interest.

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